package com.demo.utils;

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;

/**
 * @author wang
 */
public class IpUtil {
  private IpUtil() {
  }

  private static final String UNKNOWN = "unknown";

  /**
   * 获取ip
   *
   * @param request
   * @return
   */
  public static String getIpAddr(HttpServletRequest request) {
    String ipAddress;
    try {
      ipAddress = request.getHeader("x-forwarded-for");
      if (ipAddress == null || ipAddress.length() == 0 || UNKNOWN.equalsIgnoreCase(ipAddress)) {
        ipAddress = request.getHeader("Proxy-Client-IP");
      }
      if (ipAddress == null || ipAddress.length() == 0 || UNKNOWN.equalsIgnoreCase(ipAddress)) {
        ipAddress = request.getHeader("WL-Proxy-Client-IP");
      }
      if (ipAddress == null || ipAddress.length() == 0 || UNKNOWN.equalsIgnoreCase(ipAddress)) {
        ipAddress = request.getRemoteAddr();
        if (ipAddress.equals("127.0.0.1")) {
          // 根据网卡取本机配置的IP
          InetAddress inet = InetAddress.getLocalHost();
          if (inet != null) {
            ipAddress = inet.getHostAddress();
          }
        }
      }
      // 对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照','分割
      // "***.***.***.***".length()
      // = 15
      if (ipAddress != null && ipAddress.length() > 15 && (ipAddress.indexOf(",")) > 0) {
        ipAddress = ipAddress.substring(0, ipAddress.indexOf(","));
      }
    } catch (Exception e) {
      ipAddress = "";
    }
    return ipAddress;
  }
}
